UN Secretary-General Antonio Guterres called for an immediate end to fighting in Ethiopia's Tigray region Monday, saying the country was being torn apart by war.

"The situation in Ethiopia is spiraling out of control. Violence and destruction have reached alarming levels," Guterres told reporters.

"Hostilities in the Tigray region of Ethiopia must end now," he said, adding an appeal for the "immediate withdrawal and disengagement" of Eritrean armed forces from Ethiopia.

Guterres's comments came as Ethiopia's government vowed on Monday to seize control of airports and other sites in Tigray, shrugging off a call from the African Union for an immediate and unconditional truce.

The nearly two-year-old conflict has unleashed a massive humanitarian crisis in Tigray and other parts of northern Ethiopia, with at least two million people driven from their homes and millions more in need of aid.

Guterres said that even before fighting restarted, 13 million people lacked adequate food in the regions of Tigray, Amhara and Afar.

He said aid deliveries into Tigray have been halted for seven weeks and assistance to the other two regions disrupted.

"All parties must allow and facilitate the rapid and unimpeded passage of humanitarian relief for all civilians in need," he said.

"There is no military solution. Civilians are paying a horrific price" in the conflict, he added.

Guterres called for the urgent resumption of talks to achieve a long-lasting political settlement.

"The United Nations is ready to support the African Union in every possible way to end this nightmare for the Ethiopian people," he said.